1. Field of the Invention
Embodiments of the present invention relate to a mechanically set packer suitable for use to isolate a zone in a wellbore. In one embodiment, the packer includes a pressure balanced mandrel to facilitate release of the packer. In another embodiment, the packer includes a pressure balanced mandrel to prevent application of excessive hydraulic force on the packing element. In yet another embodiment, the present invention relates to an assembly of packers for isolating a zone within a wellbore.
2. Description of the Related Art
In certain wellbore operations, it is desirable to “straddle” an area of interest in a wellbore, such as an oil formation, by packing off the wellbore above and below the area of interest. A sealed interface is set above the area of interest and another sealed interface is set below the area of interest. Typically the area of interest undergoes a treatment, such as fracturing, to assist the recovery of hydrocarbons from the straddled formation.
A variety of straddling tools are available, the most common being a cup-type tool. These tools are effective at shallow depths but may have maximum depth limitations at around 6,000 feet due to the swabbing effect induced on the wellbore liner by the tool coming out of the hole. Another type of tool includes hydraulically actuated packers disposed above and below an area of interest. However, this hydraulically actuated tool relies on a valve to open and shut to allow a fluid back pressure to set the packers, which is susceptible to flow cutting during pumping operations.
There is a need, therefore, for a mechanically actuated packer having a pressure balanced mandrel. There is also a need for a mechanically actuated packer whose actuation or de-actuation is not affected by the fluid pressure flowing therethrough. There is a further need for a wellbore isolation assembly equipped with a tension actuated packer having a pressure balanced mandrel.